Contemporary a cappella group theBates CollegeCrosstoneswill compete on the season-four premiere of WGBH’s televised singing competition “Sing That Thing!,” to be broadcasted locally by Maine Public TelevisiononSaturday, May 5 at 4:30 p.m. The episode will also feature Boston Jazz Voices and Chelmsford High School’s The Thursdays. After the performance, coaches Annette Philip, Anthony Trecek-King, and Jared Bowen will offer constructive feedback to each group and decide which will move on to perform in the finale later in the season.